It has been known that catechins in tea polyphenols have various effects such as an antioxidating effect (Japanese Patent Laid-open No. S59-219384 and Japanese Patent Laid-open No. H1-268683), antimicrobial and bacteriostatic effects (Japanese Patent Laid-open No. H2-276562 and Japanese Patent Laid-open No. H3-246227), an inhibitory activity for cholesterol increase (Japanese Patent Laid-open No. S60-156614), an inhibitory activity for blood pressure increase (Japanese Patent Laid-open No. S63-214183) and an inhibitory activity for blood glucose increase (Japanese Patent Laid-open No. H4-253918).
An increased catechin intake is needed to attain such excellent physiological effects. Tea polyphenol compositions containing high concentrations of catechins have been developed so far.
There have been known, for example, a method of purifying polyphenolic compounds (catechins) to a high purity by contacting with lignocelluloses (refer to Patent Document 1), a method of producing tea catechin compounds in high yields by separating out the unrequired fraction with gel column chromatography using aqueous solutions of hydrophilic organic solvents with concentrations appropriately varied (refer to Patent Document 2), a method of producing highly pure catechins by eliminating caffeine in tea leaves by passing a tea extraction through a liquid chromatography column packed with an adsorbent such as cyclodextrin polymer (refer to Patent Document 3) and the like.
Patent Document 1: Japanese Patent Laid-open No. H7-238078
Patent Document 2: Japanese Patent Laid-open No. H1-175978
Patent Document 3: Japanese Patent Laid-open No. H10-67771